This is an extension of biological basis of behaviour with special reference to neurotransmitters and neuromodulators. The mechanism of action of various antipsychotic and anxiolytic drugs will be discussed with reference to their cognitive, emotional and behavioural effects. Students will be introduced to psychiatric diagnostic categories, the uses and limitations of the classificatory systems (DSM V and ICD 10). Treatment and relapse prevention strategies will also be discussed. The course presents to trainees theories of substance abuse and addiction. Psychosocial effects of illegal substances in the Ghanaian context will be addressed. Treatment approaches, rehabilitation and relapse prevention will also be discussed.